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McQuay Screw Compressor

I have a client who is asking if I can retrofit his McQuay Frame 3200 screw compressor on a water cooled chiller with a variable speed drive to improve energy efficiency. He can get a government subsidy to fund the works. My concern is with heat and oil and other unknowns when speed controlling the compresor.

Control is not an issue. It has been retrofitted with aftermarket controls and we have full access to it's complete function set and software.

Can anyone tell me how these Frame 3200's respond to speeds at less than 100%?

Re: McQuay Screw Compressor

Hi Steve,

True enough. I've heard plenty of stories about shredded star gate wheels and stuff stripping off components, but never seen it myself. ( I hope I never see it - for that matter) I heard that they fixed the issue with breaking wheels about 5 years ago. This compressor is only about 3 years old so we might have half a chance.

I suppose the easiest way is to just buy a variable speed chiller - but it's impossible to justify to the bean counters when it is so new - especially if it is possible to retrofit it for a lot less cost.

Re: McQuay Screw Compressor

I gather that McQuay fixed a load of issues with the Frame 4, but then I thought they have been around for longer than 3 years? Unless your machine is second hand or sat around someplace for a while?

I gather from my boss that when he attended the IKK in Germany this year, he saw a few manufacturers had begun producing compressors specifically to be used for variable drives. Hanbell are one, not sure who else. I guess there must be longevity issues with a standard slider load screw, perhaps with lubrication at lower speeds?

Re: McQuay Screw Compressor

Originally Posted by Scramjetman

Hi Steve,

True enough. I've heard plenty of stories about shredded star gate wheels and stuff stripping off components, but never seen it myself. ( I hope I never see it - for that matter) I heard that they fixed the issue with breaking wheels about 5 years ago. This compressor is only about 3 years old so we might have half a chance.

I suppose the easiest way is to just buy a variable speed chiller - but it's impossible to justify to the bean counters when it is so new - especially if it is possible to retrofit it for a lot less cost.

I'm thinking a good first port of call would be Mr Tony Pitt at the factory in Rome.

Call Marco at the factory on +39 0693731311 and ask him to put you through to Tony up in the compressor R&D section.

Re: McQuay Screw Compressor

Thanks for the input guys. I spoke to the client about the risks and he's elected not to pursue this, - which I think is wise. Tony's office looks like the lab of a mad scientist. All he needs is some bubbling chemicals and a some rotating governor weights somewhere to make it complete.

Re: McQuay Screw Compressor

Originally Posted by Scramjetman

Thanks for the input guys. I spoke to the client about the risks and he's elected not to pursue this, - which I think is wise. Tony's office looks like the lab of a mad scientist. All he needs is some bubbling chemicals and a some rotating governor weights somewhere to make it complete.

I would agree with you if it was my office! I have the usual desk and chair like everyone else! I don't know how a compressor test cell got upgraded. By The way, the VFD is a standard option for mcQUAY and pays for itself in about 18 months - your client got the wrong advice.

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